$blue: blue;
$column: 200px;

.menu {
  width: calc(4 * $column);
}
.menu_link {
  background-color: $blue;
}

.notice {
  @if 3<6 {
    background-attachment: fixed;
  } @else {
    bottom: 2px;
  }
}

@for $i from 1 to 3 {
  .b-$i {
    width: $(i) px;
  }
}
